Influence of curing time and temperature on the mechanical properties of resins manufactured through stereolithography

Abstract Additive manufacturing technologies are widely used and provide unique advantages over other manufacturing techniques. However, to achieve the optimal properties of an additive manufactured product, knowledge about the specific tool and parameters is required. A suitable approach to understand the parameters and the influence on the final properties is to investigate the variations of a mechanical property based on the fluctuation of the manufacturing parameters. This study focuses on determining the influence of the curing temperature and time under UV light (405nm wavelength) on the tensile properties of specimens obtained through stereolithography (SLA). This aspect was attained by manufacturing batches of specimens from a urethane dimethacrylate (UDMA) based resin (commercial name Formlabs Tough 2000®) and then curing them for different periods of time (from uncured up to 180 minutes). The samples were tested and, based on the resulting stiffness and strength, the optimal curing time of 90 minutes was established. The value of this parameter was used to investigate the influence of the temperature at which the specimens are cured, with a variation from 25 °C to 80 °C, resulting with an optimal curing temperature of 60 °C. The study also concluded that after a certain temperature, the stiffness is declining, even though the strength of the specimens reaches a plateau-like region.